Article

“Solid state fermentation for the production of alkaline protease by Bacillus cereus 1173900 using proteinaceous tannery solid waste.

Current science (Impact Factor: 0.91). 01/2011; 100:726-730.

ABSTRACT Animal fleshing, the major proteinaceous solid waste
generated from leather industry, was used as substrate
for the production of alkaline protease by Bacillus
cereus 1173900 in solid-state fermentation (SSF).
Maximum protease activity of 12,310 U/g was observed
at 60 h in SSF crude extract. The extracted
protease enzyme was purified by 53.64-fold through
ammonium sulphate precipitation and chromatography
separation in Sephadex G-100. The purified protease
had a specific activity of 201.6 (U/mg). The molecular
weight of the purified enzyme was 66 kDa, determined
by SDS–PAGE. The zymogram also revealed a clear
hydrolytic zone due to proteolytic activity, which
coincided with the band obtained with SDS–PAGE.
Enzyme activity was inhibited by EDTA, suggesting
that the enzyme belongs to metalloprotease(s).

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    ABSTRACT: Cow dung, a cheap and easily available source of energy, was used as the substrate for the production of alkaline protease by solid-state fermentation using the Bacillus subtilis strain VV. In order to achieve the maximum yield of this enzyme, the following optimum process parameters are needed: fermentation period (72 h), pH (10.0), moisture content (140%), inoculum (25%), temperature (30-40°C), carbon source (2% (w/w) maltose) and nitrogen source (1% (w/w) urea). The protease was stable over a broad temperature range (30-50°C) and pH (8.0-10.0), with maximum activity at 50°C and pH 10.0. Among the divalent ions tested, Ca(2+) (0.01 M) increased enzyme activity. The purified protease, after being subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis, was found to have a molecular mass of 38.5 kDa. The enzyme was solvent-and surfactant-stable and showed activity even after 24 h incubation along with various commercially available detergents. This enzyme possessed dehairing properties for animal hide after 16 h of incubation at room temperature. From these results it is evident that cow dung is a potential substrate for the production of a detergent-stable, dehairing protease by B. subtilis. This enzyme has a lot of potential applications in the detergent and leather-processing industries.
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